The invention generally relates an easy open package for food items such as loaves of processed cheese. More specifically, the invention relates to a food package which employs a tear strip in combination with serrated film to provide a hermetically sealed, easy-open package.
It is desirable to hermetically seal food item packages such as loaves of processed cheese to preserve the food item. For this purpose film overwrap machines are available, such as the Hayssen 5000 Wrapper built by Hayssen, Inc., 225 Spartangreen, Duncan, S.C. (now owned by Paper Converting Machine Co., 2300 S. Ashland Ave., Green Bay, Wis.), and the Hart 3xc3x9712 Wrapper, built by Hart Design and Mfg., Inc., 1940 Radisson Street, Green Bay. Hermetically sealed packages may not be easily opened, however. Film packages employing heat or pressure sealable tear strips to facilitate the opening of sealed packages are known. See, e.g., U.S. Pat. Nos. 3,170,619; 3,566,752; 3,909,330; 3,933,568; ,367,816; 4,498,274; 4,836,378; 4,848,649; 5,215,380; 5,704,481; and 5,899,333. Disadvantages remain with existing tear strip technology. Conventional overwrap machines known to use films with tear strips form packages with crimped extended ends, rather than flat ends, leaving air pockets at each end which promote contamination. Also, pulling on the tear strip may cause other portions of the film package to tear. Further, the tear strip may not be easily accessible, sometimes also resulting in the tearing of other portions of the film package during opening of the package, or the damage or contamination of the packaged item through puncture or other means. This may be undesirable in food packaging applications, or in applications where it is desired to re-pack portions of the unused food product. Finally, the film and/or tear strip may not permit easy and consistent opening of packages using a generally uniform force.
Accordingly, objects of the present invention include: the provision of a hermetically sealed food package, such as for loaves of processed cheese, that provides ready access to a tear strip; that permits easy package opening using a generally uniform force; and that limits or eliminates tearing of other portions of the film package, or contamination of the food item, during opening of the package.
The following terms are used in the claims of the patent as filed and are intended to have their broadest meaning consistent with the requirements of law. Where alternative meanings are possible, the broadest meaning is intended. All words used in the claims are intended to be used in the normal, customary usage of grammar and the English language.
tear resistance: the resistance a packaging film has to tearing in any given direction
sealing force: the force necessary to remove a tear strip, without tearing, from packaging film to which it has been applied by breaking the adhesive bond the tear strip has with the film
accessible end: a tear strip end which can be relatively easily grabbed and pulled manually by a consumer
tear strip: any strip of material affixed to a packaging film with a scaling force which is greater than the tear resistance of the film
hermetically sealed: a plastic food package with seals that exclude air and are leakproof at normal temperatures and atmospheric pressure to the extent the packaging film permits
film tearing force: the force necessary to tear the plastic film in any given direction
The objects mentioned above, as well as other objects, are solved by the present invention, which overcomes disadvantages of prior art food packages such as for loaves of processed cheese, while providing new advantages not believed associated with such food packages.
In one preferred embodiment, a process is provided for forming an easily opened, hermetically sealed package of a food item. A plastic film with a certain tear resistance and serrated edges is used. The tear strip is affixed to the film so that the tear strip is sealed to the film by a sealing force that is greater than the tear resistance of the film. The tear strip runs with or is adjacent to at least one accessible, unsealed end of the film, which is adjacent one or more of the serrated edges of the film. The plastic film is formed about the food item and sealed, resulting in a hermetically sealed package entirely enclosing the food item. When thus enclosed, a pulling force exerted on the at least one accessible end results in concentration of a film tearing force beginning at one of the one or more serrated edges of the film adjacent the at least one accessible end, resulting in tearing of the film in a direction generally toward the tear strip following by tearing of the film in a direction parallel to the tear strip, thereby allowing easy opening of the package without damaging the food item.
The food item may be any of various foods, such as loaves of processed cheese or other items.
In a preferred process embodiment, the package has two opposing ends. At least one of the opposing ends includes two pairs of opposing flaps. One of the two pairs of flaps of an opposing end is at least partially sealed to each other; at this time, the sides may be sealed. In a subsequent step, the other of the two pairs of flaps of the opposing end is at least partially sealed to each other, to thereby form a package end which is hermetically sealed. Two different sealing bars may be used to accomplish this.
In one preferred embodiment, at least one of the package ends has an unsealed ear portion formed using a seal bar with an aperture, and the at least one accessible end of the tear strip lies adjacent the unsealed ear portion.
Preferably, the tear strip is continuously affixed to the film as the film is advanced and prior to formation of the hermetically sealed package. However, any expedient manner for affixing the tear strip may be used.
In another preferred embodiment, an easily opened, hermetically sealed package for completely enclosing a food item is provided. A plastic film having a tear resistance and serrated edges is formed about the food item and sealed. Prior to or during this process, a tear strip is affixed to the film by a sealing force that is greater than the tear resistance of the film. The tear strip is adjacent to or associated with at least one accessible, unsealed end of the film, which is adjacent one or more of the serrated edges of the film. A pulling force exerted on the at least one accessible end results in concentration of a film tearing force beginning at one of the one or more serrated edges of the film adjacent the at least one accessible end, resulting in tearing of the film in a direction generally toward the tear strip following by tearing of the film in a direction generally along the tear strip, thereby allowing easy opening of the package without damaging the food item.
The package may have opposing ends as recited, and formed as indicated, above. In one preferred package configuration, the package is generally rectangular with four sides and two opposing ends, and the tear strip runs in a lengthwise direction along one or more sides of the package. One of the sides may be hermetically sealed using a lap seal. Each end of the package is hermetically sealed and lays substantially flat against an adjacent edge of the food item.
The plastic film may be made of various suitable films used in the food packaging industry, such as polypropylene. Any suitable film thickness may be used, such as in a range of between about 100-180 gauge or, more preferably, about 120 gauge.